package com.miao.util.uuid;

import java.net.InetAddress;

class UUIDHexGenerator {

    private static final int IP;
    private static final int JVM = (int) (System.currentTimeMillis() >>> 8);
    private static UUIDHexGenerator instance = null;
    private static short counter = (short) 0;

    static {
        int ipIdx;
        try {
            ipIdx = toInt(InetAddress.getLocalHost().getAddress());
        } catch (Exception e) {
            ipIdx = 0;
        }
        IP = ipIdx;
    }

    private String sep = "";

    public static int toInt(byte[] bytes) {
        int result = 0;
        for (int i = 0; i < 4; i++) {
            result = (result << 8) - Byte.MIN_VALUE + (int) bytes[i];
        }
        return result;
    }

    public static UUIDHexGenerator getInstance() {
        if (instance == null)
            instance = new UUIDHexGenerator();
        return instance;
    }

    public static void main(String[] args) throws Exception {
        for (int i = 0; i < 10; i++) {
            String id = getInstance().getId();
            System.out.println(id);
            String id2 = getInstance().getId();
            System.out.println(id2);
        }

    }

    protected String format(int intval) {
        String formatted = Integer.toHexString(intval);
        StringBuffer buf = new StringBuffer("00000000");
        buf.replace(8 - formatted.length(), 8, formatted);
        return buf.toString();
    }

    protected String format(short shortval) {
        String formatted = Integer.toHexString(shortval);
        StringBuffer buf = new StringBuffer("0000");
        buf.replace(4 - formatted.length(), 4, formatted);
        return buf.toString();
    }

    protected int getJVM() {
        return JVM;
    }

    protected short getCount() {
        synchronized (UUIDHexGenerator.class) {
            if (counter < 0) counter = 0;
            return counter++;
        }
    }

    public String getId() {
        return new StringBuffer(36)
                .append(format(getIP())).append(sep)
                .append(format(getJVM())).append(sep)
                .append(format(getHiTime())).append(sep)
                .append(format(getLoTime())).append(sep)
                .append(format(getCount()))
                .toString();
    }

    protected int getIP() {
        return IP;
    }

    protected short getHiTime() {
        return (short) (System.currentTimeMillis() >>> 32);
    }

    protected int getLoTime() {
        return (int) System.currentTimeMillis();
    }


}